Many herbicides injure crop plants at rates necessary to control weed growth. However, to be effective an herbicide must cause minimal damage, preferably no damage, to the beneficial crop while maximizing damage to weed species which infest the locus of the crop.
Herbicides have gained a high degree of commercial success because it has been shown that such compounds can increase crop yield and reduce harvesting costs. Some of these herbicides include types such as triazines, halogenated acetanilides, carbamates, thiolcarbamates, benzoic acid derivatives, urea derivatives and the like.
In some cases, a crop species may be susceptible to the effects of the herbicide. To preserve protection of crop species from herbicide injury along with the concomitant herbicidal effectiveness of weed species, use of chemical compounds called antidotes or safeners have been employed. See, for example, U.S. Pat. Nos. 4,021,224 and 4,230,874.
Although the effects of antidotes against herbicide injury can be established under field and greenhouse conditions the physiological and biochemical mechanisms of action have not been established for all compounds. Nevertheless, the use of antidote compounds with herbicides is a widely accepted agronomic practice. These compounds are used on crops including agronomic and vegetable species.
The isoxazolidinone compounds have been found to be very effective herbicides with broad general herbicidal activity against a wide variety of plant species. Many active 3-isoxazolidinone herbicidal compounds are disclosed in U.S. Pat. No. 4,405,357 which is incorporated herein in its entirety by reference. The method of controlling vegetation with the compounds comprises applying an herbicidally effective amount of the isoxazolidinone, usually with an inert carrier, to the area where herbicidal control is desired.
The isoxazolidinone compounds have been found in some instances to adversely affect or interfere with the culture of a variety of crops. In particular, gramineous crops such as corn are sensitive to the application of effective weed controlling rates. Therefore, the effective use of these herbicides for controlling weeds in the presence of such crops is further enhanced by, or may require in many instances, the addition of an antidotally effective amount of a compound, which is antidotally effective with the isoxazolidinone herbicide.
It is the objective of this invention to increase the spectrum of crop plants in which an active herbicidal 3-isoxazolidinone compound may be used without injury to the crop and without decreasing the herbicidal efficacy against weeds.